Pediatric diabetes looms as an emerging health care crisis in America. Both type 1 and 2 diabetes share common developmental issues that require successful adolescent/parent interactions to promote healthy self-care, particularly in diet and exercise behaviors. A Prevention Program to avoid adolescent self-care deterioration in T1D, the more virulent form, is proposed with a 3-site study that has a 23% minority representation. To facilitate maximum translation to routine clinical care, a brief, office-based treatment is planned (4, 30-min sessions) that will incorporate instruction in authoritative parenting, along with relevant coping skills of communication, problem solving, conflict resolution, and cognitive refraining. Treatment will be accompanied by comprehensive assessment to describe 1) correlates of self-care, including novel memory predictors, 2) moderators of treatment efficacy, and 3) innovative assessment of immediate response-to-treatment (RTT) behavioral trajectories. RTT will use data from 24-hour disease care interviews obtained during treatment inter-sessions for precise behavioral tracking of immediate session efficacy. We will map behavioral trajectories in response to treatment sessions to better understand what previously has been a 'black box'of year-long treatment. The proposed multi-site study with 3 locations should facilitate generalizability of results and the resultant large N of 190 should increase sensitivity to treatment effects. Powerful latent growth curve analyses and structural equation modeling will be utilized for data analysis, along with more traditional statistical techniques. A comprehensive biopsychosocial framework will be adopted that includes biological, psychological and sociofamial measurements of youths with diabetes and their parents. Approximately 190 11- to 14-year-olds will be assigned in a 5:1 proportion to either brief, office-based treatment or an attention control group. Previously, treatment groups have spanned wide age ranges such that the proposed narrow age range in the early adolescent years (11-14) should minimize broad developmental differences that may have obscured earlier results. Most subjects will be followed for up to 2 years'post-intervention. Better biometric outcomes (blood glucose levels, glycohemoglobin levels, fewer adverse events), along with better psychosocial outcomes (continued parental involvement in disease care, more frequent/better disease care), is predicted relative the attention control group.